The present invention relates to exhaust systems in general and to cross-exit exhaust systems utilizing cross coupling via a common chamber to interconnect different portions of the exhaust system for silencing purposes.
Prior art approaches to noise reduction, especially in higher performance engines, has been obtained by utilizing cross coupling passageways between left and right exhaust conduits coming from opposite sides of the engine block from manifolds associated with a particular bank of cylinders. Such approaches have been commonly referred to as xe2x80x9cH-pipexe2x80x9d or xe2x80x9cX-pipexe2x80x9d exhaust configurations. One example of the X-pipe approach, which essentially is a variation of the older H-pipe approach is shown in U.S. Pat. No. 4,800,719.
All the known prior approaches utilizing the H or X-pipe interconnection schemes involve passing exhaust gases and associated pressure pulses in the first and second (or left and right) exhaust pipes coming from the opposite sides of the engine past the common cross-over point wherein the exhaust and associated pressure pulses are flowing past that common chamber in the same direction.
We have found that improved cancellation of low frequency exhaust noise is attained in such cross coupling exhaust systems where the gases and related pressure pulses flow past the connection point, or common chamber, in opposite directions.
Accordingly, an exhaust system for use in a vehicle having an internal combustion engine with first and second cylinder banks, each having respective first and second exhaust manifolds, comprises a first conduit adapted to be coupled to the first manifold, a second conduit adapted to be coupled to the second manifold, said first and second conduits extending toward each other downstream of their respective manifolds to a cross-over point, and a common chamber in fluid communication with the first and second conduits substantially at the cross-over point, whereby exhaust gases and associated pressure pulses in the first conduit flow past the common chamber in a direction substantially opposite to flow of exhaust gases and associated pressure pulses in the second conduit.